The use of large rotary hammers is an effective way to bore holes into stone or concrete. Unfortunately, there are users who improperly use this type of power tool. For instance, when a user is holding the tool upright while drilling downward, there is a tendency to relax the grip on the rear handle. Since the rotational grab of the tool is minimized by the hammering action, it only takes a little force from the rear handle to stabilize the tool. The careless operator may not use the side handle, which is specifically designed to allow the user to manage the high torque created by stall conditions. Unfortunately, when the rotating bit encounters a piece of solid rock or rebar buried within the material, a jam condition could occur. When the bit jams, the rotational torque is instantly transferred to the tool housing. Since the user only has a slight grip on the rear handle, the tool housing will rotate. The clutch within the tool is typically set to a high level so as to handle relatively high torque situations. Even if the trigger is released as the tool twists out of the user's hand, the rotational motion of the tool is sufficient to injure the user.
Therefore, it is desirable to provide a method for controlling a power tool, such as a rotary hammer, at the onset of such a bit jam condition.